This invention belongs to the field of tools and particularly to threaded slidable jaw adjustment wrenches, PTO Class 81, Subclasses 155, 163, 165 and 170.
A typical socket wrench set has a plurality of socket wrenches, each sized for a specific bolt, a socket wrench drive handle and one or more extensions, each with a drive stud. Each socket wrench has at one end a hexagonal socket opening for a specific size bolt, and has at the opposite end a drive-studreceiving recess. Socket wrench drive handles are available in a variety of shapes and styles including L and T shapes, ratchet drives, and there are straight extensions of different lengths. Each has a drive stud at one end which fits into the drive stud receiving recess in each socket wrench.
The utility of a socket wrench drive handle can be extended by means of a set of crow foot wrenches. These are short, open-ended wrenches, each with a drive-stud-receiving recess. Crow foot wrenches add versatility to a drive handle by enabling it to work in a hard-to-reach place where a socket wrench would not fit. A ratchet drive handle of the ratchet type provides quick, easy movement in tight quarters, plus the transverse accessibility of an open ended wrench.
Typically, crow foot wrenches are in sets of ten or so, each in a different bolt size. As with any set of loose, differently-sized parts, there is always a problem of keeping the set intact. To avoid this problem, adjustable crow foot wrenches have been proposed so a single wrench can be used on a range of different sized bolts. Examples are shown in U.S. Pat. Nos. 2,600,617 and 4,277,991. These have an adjustment worm member which is manually rotatable to make the jaws fit a particular bolt size. This is somewhat comparable to the worm adjustment utilized on crescent wrenches which has a serious drawback in that it loosens in use and constantly requires retightening. On a crescent wrench, although a nuisance, this can be tolerated; but for a crow foot wrench, possibly on the end of a long extension in an awkward, out-of-the-way location, this would not be practicable.